The oro-pharynx is that area behind the oral cavity, below the naso-pharynx and above the laryngo-pharynx and the oesophageal entrance. During the administration of some general anaesthetics it is advisable to insert a throat pack to close off part of the oro-pharynx and/or laryngo-pharynx. The purpose of this is to eliminate the passage into the lungs of any harmful foreign material such as blood, saliva, pus, tooth or parts of teeth, and so on. The oro-pharyngeal pack occludes the oral airway and thereby promotes the nasal inhalation of anaesthetic gases. Care must be taken, however, to ensure that the nasal airway is not impaired by a backward displacement either of the tongue or of the soft palate.